


only way to be sure

by kellifer_fic



Category: Teen Wolf (TV)
Genre: Alternate Universe - Aliens, Alternate Universe - Space, M/M, POV Derek, Pre-Relationship, Space Marines
Language: English
Status: Completed
Published: 2013-04-30
Updated: 2013-04-30
Packaged: 2017-12-10 00:06:36
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 14,603
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/779524
Author URL: https://archiveofourown.org/users/kellifer_fic/pseuds/kellifer_fic
Summary: <blockquote class="userstuff">
              <p>Derek might hate stasis but he <i>loves</i> combat drops.</p>
            </blockquote>





	only way to be sure

**Author's Note:**

> Amazing companion art by mific [here!](http://archiveofourown.org/works/779477)

Derek hates being in stasis.

He understands the need for it. It's the only way to travel vast distances without being a withered old man by the time you get anywhere useful. It's just, slipping into that pod makes his hackles raise every damn time, the wolf unsettled by how vulnerable it makes him, makes his squad. They're exposed to any number of disasters with no way to defend themselves. Derek is intimately aware of what can happen on a ship when no one is watching over you.

If getting in is pretty bad, getting out is worse. He feels weak and shaky, bleary. He doesn't get sick anymore, that passes as the body adjusts but he can already hear Jackson jeering at their newest green recruit who is losing the contents of his stomach over the side of his pod. Derek knows he should get up, put an end to Jackson's taunts and make sure the kid is okay, but their pilot beats him to it, says something that Derek doesn't quite make out but gets Jackson to shut up, fast.

Derek looks across at the next pod over from his, sees Boyd's long legs hanging out, the rest of him yet to follow. Derek rubs a tired hand over his eyes then stands. He fights off the shakiness of his legs because he doesn't want anyone to see it, not his squad and especially not the company men they're escorting on this little jaunt.

"Everyone up!" he barks, bites down on the smile that threatens when he hears Boyd groan.

"Sarge, have a heart," Boyd complains, finally levering himself upright. Derek sees Isaac jerk like he was goosed, brows furrowed and hair mashed flat on one side, looking disoriented. His instincts had forced him up at his alpha's voice but his brain looks like it's yet to come online. Erica is already striding past, stretching and looking unfairly bright. She's wearing the same sagging boxer shorts they all are but she might as well be wearing full kit by her jaunty stride. She flicks Isaac in the forehead as she goes by and he grunts and flips her off with a grimace.

Derek looks towards the nav terminal and Boyd is already sitting at it, their pilot hunkered over him, tying her hair back in a loose ponytail and already dressed in her flight suit. Derek is a little unsettled to have an Argent as their pilot considering they're escorting two of Argent Corporation's higher-ups, but she's Enlisted, earned her wings on her own and he respects that. He knows she probably got tapped for this mission because Argent Corp pulled some strings, but people he trusts have told him she's solid and he knows she's done enough combat drops not to take any shit from anyone about how she got where she is.

He couldn’t call her Argent because there are three people in this hold that could answer and she'd grinned at him before they slept, said _Allison is fine_ so now he calls that instead, nods when she gives him a thumbs up that indicates that they woke because they were where they were supposed to be and not for any other reason.

Derek finally makes his way over to the shaky recruit's pod. Scott McCall seems like a good kid but he's a little trusting and a _lot_ young and Derek is waiting for the rest of his squad to eat him alive. Scott needs to do something to earn their respect soon and he's not going to get the chance on a milk run like this one.

Scott is hunched over still, breathing deep. The floor is grated on either side of the pods just for this reason, that most people lose whatever they last ate and then some on waking. It’s the less glamorous side of space travel, that and the endless boredom. "It'll pass in a few hours," Derek offers, eying Scott's sweat-slick back. Most normal people can take up to two days to recover from stasis flu but wolves recover faster.

"I don't wanna feel like this for that long," Scott says and holds a hand out to Derek. He immediately gets what the kid wants. Seems he's a little tougher that they thought and might earn his place faster than Derek gave him credit for.

"You sure?" Derek asks.

Scott nods without looking up. "Yes, just-"

Derek doesn't give Scott a chance to finish or warning, just reaches out and snaps two of his fingers. Scott grunts and snatches his hand back, then swears, long and colorfully. Isaac, who's managed to finally pry himself out of his pod, always the last up, reaches around Derek and smacks Scott on the shoulder.

"Badass," he enthuses. Scott looks up, offers a shaky smile. His fingers are already knitting and the pallor is easing from his skin, the healing process kicked along by the broken digits.

"I just didn't want to throw up again," Scott says and Isaac chuckles before offering Scott a hand up and they both totter over to their lockers. Boyd has left Allison at the nav terminal and bumps a shoulder against Derek's. The touch serves two purpose, a contact greeting and scent-sharing since the sterile pods rob them of anything but their own chemical smell.

"I guess he'll do," Boyd says, nodding in Scott's direction. "Better than Greenburg anyway."

"Anyone's better than Greenburg," Derek agrees and Boyd laughs and nudges him again before making his way to his own locker.

*

They have a human lieutenant. Considering a werewolf has yet to pass the rank of sergeant, it's to be expected, but Derek still feels a pulse of resentment, that humans understand so little of the werewolf hierarchy that they expect them to follow a human's orders when they have an Alpha present. Derek doesn't have anything against humans in his squad, but he's had some problems in the past. There have been misunderstandings that were viewed as insubordination.

Last year though, they were lucky to be assigned Lieutenant Stilinski. Known as Sheriff by everyone, he's aware enough of the way werewolves work to filter his commands through Derek so the betas aren't conflicted. Over the last two years of having him, Derek's learned to trust the man with his pack and himself which he never thought he'd do.

They got ship out orders three weeks ago, babysitting a pair of corporate draggers to go check out a downed comm link in the ass end of space. Sheriff usually has a way of finessing them out of the purely grunt and thump duties which is all werewolf squads can normally hope for, so Derek was surprised when he didn't even try this time, had a grim set to his mouth when he told Derek they were doing this one, no arguments.

Derek doesn't ask why, because he’s learned there's always a reason Sheriff does what he does that might not be immediately apparent. It doesn't stop his _squad_ from grumbling, and loudly when they're all called together for a briefing when everyone’s upright. Derek stands up front with Sheriff while the wolves gather. The two Argent Corporation representatives, both Argents themselves, it's apparently a family reunion that Allison didn't look too pleased about, are hovering a few feet away with a Synthetic they call Daehler at Gerard's left shoulder.

"Y'know, I gave up on babysitting when I was a thirteen year old girl," Lydia snarls, crouched next to Jackson who looks bored and unimpressed, his two most recycled expressions.

"Martin-" Derek starts to bark but as always, when Lydia puts voice to her displeasure, the others all feel compelled to follow suit.

"It's going to be a jacked transmitter line. This is the job for a tech team," Boyd agrees.

"Hey LT, I heard you asked for this mission. There something you aren't telling us?" Isaac pipes up. Sheriff slides Derek a glance and Derek steps forward, grabs Isaac by the scruff and gives him a non-too-gentle shake.

"It's above your pay grade to ask questions," Derek snaps, tossing Isaac back towards where he was hunkered. Isaac curls into himself, cowed.

"We're hoping you're right," the older Argent, Gerard, pipes up. He's got a smile on his face that doesn't reach his eyes and Derek is unsettled by him, can tell that the other wolves are too. Chris, the younger of the two, rubs a tired hand over his face. His eyes keep cutting to Allison who is resolutely looking anywhere but back at him.

"It's possible it's just a comms problem but we need to be prepared for anything. LV-426 is the first planet to be colonized outside of the controlled territories and the reason we're concerned is that we found out that there wasn't a proper F&F spec done," Chris explains. An F&F spec is a biological and botanical sweep, making sure that there aren't any poisonous or hostile indigenous life already on site. The grumbling starts up again, this time concerned.

"All that means is that we go in hot," Derek says levelly, meeting every eye until the wolves settle again. "Do it by the numbers, sweep and clear the inhabited areas and don't take any stupid chances. Got it?"

"Sir, yes sir," his squad says as one and Derek nods, defers back to Sheriff who starts assigning tasks for set down with a practiced eye for efficiency. Derek sees Chris Argent approach Allison when everyone splits off and her skirt him neatly by collaring Scott and using him like a werewolf shield. Derek knows it really isn't his business or his place to ask _Chris_ what the hell is going on, so he makes a mental note to corner Allison, make sure a little family drama isn't going to disrupt a smooth mission.

He's not looking forward to it.

*

Derek might hate stasis but he _loves_ combat drops.

He knows it's probably insane to enjoy the sick-swoop of it, the sensation of your stomach hitting the underside of your jaw. The main reason Derek had accepted Allison’s assignment was because she'd taken him into the simulator and dropped him eight times in a row.

It was against regs to do it more than twice in a two week period.

Derek had emerged shaky, sweating and laughing fit to bust a gut and Allison had looked at him and said, "That’s the first time I’ve seen you look anything other than pissed off."

He'd harassed Sheriff until the lieutenant had signed the commission, shaking his head. "She gets so much as a broken nail and you can kiss your hairy ass goodbye."

"Everyone set?" Allison calls from the cockpit. There's a chorus of _set_ and then Derek confirms it. He can hear the smile in her voice when she says, "Three, two, one, drop!"

The transport shuttle drops out of the belly of the Beacon. There's that few seconds where everything is quiet when they're still in space, then the roar starts up when they hit atmo. Derek looks around the cabin, an ingrained habit and is relieved to see Gerard and Chris uncomfortable but otherwise okay. Jackson is whooping obnoxiously because he _hates_ combat drops but doesn't want anyone to know it.

Scott is the surprise. For a second Derek thinks that he's passed out, which isn't a good sign, but then he kind of huffs and snorts and Derek realizes he's _asleep_. Derek rolls his eyes when Erica who's strapped in next to Scott wets a finger and sticks it in his ear. Scott yelps and flails. Derek meets Boyd's eyes next who gives him a complicated facial expression which Derek can glean the meaning of anyway.

Definitely better than Greenburg. He was a puker.

*

LV-426 is a dump. Chris Argent point out the three large environmental processors and explains that they convert the toxic atmosphere into one that’ll sustain life. There's another large complex that houses the colonists, then a small shanty-like town that looks to have sprung up around it, made from anything the colonists could recycle as the world outside became available to them.

"Give humans six months anywhere and they'll stick a bar on it," Sheriff huffs, pointing at a ramshackle building with a sign that reads _LAST STOP PUB_. There's no one around, the dilapidated buildings made eerie with absence.

There's evidence that there used to be a tunnel between the landing bay for the shuttle and the main complex but it's been dismantled at some point, probably when air became breathable, to reuse for the other buildings and allow people more area to escape to. They must have been going stir crazy all in the one complex no matter how large for so long. Derek knows there's no werewolf colonists just for this reason, that they couldn't handle being boxed in like that.

"Is this wind normal?" Isaac yells in his ear, following Derek out of the landing bay first, eyes scanning and pulse rifle held against his chest.

"It's the processors. This close we're getting buffeted by what they pump out," Chris Argent responds before Derek has a chance to.

"You and Mr. Argent need to stay with the shuttle until we clear the complex," Derek says.

"I want to-"

"We have to clear the complex and then you can run around it to your heart's content. Plus, Lieutenant Stilinksi is staying to monitor vitals and comms but he has to do that for a bunch of us. He could use an extra pair of eyes." Derek knows Chris isn't really picking up what he's setting down, but he doesn't argue, simply nods and heads back inside to the shuttle.

Scott, Erica, Lydia and Jackson file out, falling naturally into formation. Boyd brings up the rear, holding onto the oversized smart gun, already clipped into his body harness. Before every mission there's a lottery on who gets to use the M56 and Boyd had gleefully claimed victory although Derek suspects he cheated somehow. It's always the quiet ones.

Derek jogs back to Allison, watching the way she's got her hand on her service pistol and is pulling a face at him, about to follow them into the complex. "You need to bring in the APC when we clear the cargo hold underneath," Derek says. "No one else can drive it worth a damn."

"My da... Chris Argent might have bought your little deflection tactics but I don't," Allison argues.

"You think we could dust off without our pilot?"

"The Synthetic can pilot the shuttle and the Beacon basically flies herself. I'm essentially redundant unless there’s a problem or you let me be part of your squad."

"We'll clear up to Operations. I'll need you to come in and track the colonist's PICs if we don't find anyone."

"Yes, Sir," Allison says, still not happy but also not willing to push on her first time out with them. The others are watching, jostling each other in their restlessness. Derek flicks a hand at Lydia who nods and approaches the two large blast doors closing off the complex from the rest of the area. She's got the patch panel open and has bypassed the security code in about fifteen seconds. She turns and throws a self-satisfied grin over her shoulder and Derek nods in approval.

Boyd moves in first, doing large sweeps with the M56, Erica on his shoulder with a motion sensor strapped to one hand. Derek watches Scott follow next with Isaac, then nods for Jackson and Lydia to proceed before he slips in. They move into the big, empty space, possibly used as a loading dock once but deserted now. There's a large door on the other end and they move through that too.

"LT?" Derek says. Sheriff has their vitals but he's also got a schematic of the complex and Derek knows they're going to need to be led through. Places like these are always rabbit warrens. There's tunnels and stairways going every which way.

"Down the stairs to sub level B4, all the way to the end then you should see data cables you can follow through to operations."

*

"Are you seeing what I'm seeing, Sarge?"

Derek glances sideways at Boyd, who's staring open-mouthed at what should be an open corridor leading down to the complex's operations area, but is instead a large barricade made up of what looks like anything that wasn't welded down. There are pulse burns along the top and bottom edges of the barricade and a large rough hole in the metal floor just in front.

"This looks melted," Erica says, hunkering down and touching the end of her pulse rifle to the caved in edges of the metal floor grating. "What can do that? Nothing can do that, right?" She looks back at Derek and her eyes are huge and concerned underneath her helmet.

"What is that?" Derek hears Sheriff ask in his ear and he makes sure to pan his own helmet camera around a little slower, aware that Sheriff is only seeing a grainy feed.

"Is that the only way to operations?" Derek asks.

"There's a maintenance crawl space under the floor on the schematic. I can't tell how big it is and if it's meant for a person or a maint droid," Sheriff says. Derek eyes the hole warily. It's the most obvious way to access the crawl space and see if they can pass through to operations, but he doesn't know if there'll be a corresponding gap on the other side of the barricade and he doesn't really want to get to the end of the space and find himself trapped.

There's a click that Derek knows means he's now on a secure channel with Sheriff, who asks, "Does it look like maybe there was some kind of riot?"

Derek moves away from the others a little, cups his hand around his ear piece. He knows the wolves will still be able to hear him, but they're distracted by gaping at the barricade, wondering what it means. "This was a bunch of colonists and their families right?" When he gets a noise of assent, he says, "Unless a group of them went homicidal all at once, I can't see a reason for _this_." He looks back at the barricade, unsettled.

"Some kind of hostile indigenous life?" Sheriff hazards.

"Could be," Derek agrees. "Chris Argent said there wasn't a proper bio scan done. Who the hell knows what's out here in the unchartered."

There's a rustle, some grumbling and then a heavy sigh and Chris Argent's voice is on Derek's comm. "There... was something," he says. Derek hears in the background Gerard Argent say something, sounding displeased.

"If you know anything that'll prevent my squad from walking in blind, you better tell me now," Derek growls, injecting as much menace into his voice as he can.

There's another dissatisfied grumble from Gerard, mostly expletives and then Chris says, "It might not be related but there were reports of a distress signal coming from outside the compound. A colonist was sent out to investigate and we lost contact right after that."

"A distress signal?" Derek says slowly. "From _on planet_?"

"Yes."

"That could've been a prison transport, pirates, _anything_ ," Derek says, disgusted. "You let an unprotected colonist go out to see what it was?"

"There was some argument for scavenge rights-"

"Oh my god, you wanted to make sure it wasn't _valuable_ before you brought the military in. Did it even occur to you that anyone floating out here probably didn't want to be found?"

"We had reason to believe it was a deep space mining vessel that had been lost. An abandoned shuttle was recovered close by-"

"You had no idea what it was," Derek grits out between his teeth. His squad is no longer distracted, all watching him with curious faces.

There's more scuffling sounds and then Sheriff is back on comms. "Hale, it is what it is. Can you access the crawlspace?"

Derek huffs, irritated, but the Lieutenant is right. His mother used to say that there was no use crying over clawed cushions. Derek makes his way back to the others, gestures for Erica to hand over the motion detector. She gives him a look that tells him exactly what she thinks of that particular order. "C'mon Reyes, I'm first in, last out always."

"What if your giant ass gets stuck?" she huffs, unhooking the motion detector from her tac vest.

"I'll be a good control. If I can get through, you all can," Derek says. He ignores the way Boyd raises an eyebrow at him. _Technically_ Boyd is bigger than he is, but he's the Alpha, he's allowed an inflated sense of self, and the difference between them in negligible when it comes to squeezing through tight spaces.

Erica rolls her eyes and hands the motion detector over. Derek clips it to his own tac vest and then lets Erica and Isaac lower him down through the messy hole. He has to almost eel in because it isn't called a _crawl space_ for nothing, but Derek figures this is more natural to him than it would be to any humans since he's on all fours when he runs.

it’s dark, the light from his helmet only giving him a wan circle of visibility a few feet in front of his face. Derek closes his eyes, reaches out with his other, more enhanced senses. There's no sound other than the underlying hum of the complex's power systems, no real smell except stale air and something sickly sweet that he can't identify. There's another scent under that, something deep and damp that he's never encountered before. It makes Derek's predator hackles rise, alert.

Derek moves forward slowly. It's a pretty tight fit, but he's got just enough clearance through the shoulders to know that Boyd will make it through also. Derek switches off his helmet light because he can’t see for shit and his other senses work better when he's not trying to. Right when his light goes out, the motion sensor screams to life and Derek feels something hit him in the face and there's the sound of frantic scrabbling.

"Son of a bitch," Derek huffs and he can hear the others calling out to him, alerted by the shrill cry of the motion sensor. Sheriff's voice is in his ear demanding he _turn his light back on dammit_. Derek reaches up, spares the precious few seconds it takes to turn his comms off so he can pinpoint the scrabbling noise and follow it.

He pushes forward, a mighty burst of speed and flicks an arm out. His hand closes on something thin that feels fragile but warm and Derek instinctively yanks backwards, even though he gets another hit to the face for his trouble. There's this horrible keening noise, a pained denial and then Derek is pulling what feels like a _person_ towards him, barely making out the figure in the gloom. When he reaches up a second hand, his fingers get tangled in colonist tags. He's momentarily distracted in surprise and the person manages to curl sideways and down so they can bite Derek on the shoulder.

Derek lets go of the ankle he'd had a hold of instinctively and the figure's away again, slipping down a side access hatch Derek hadn't noticed. Derek only hesitates for a second, before he pulls himself down and through in pursuit, coming to an abrupt halt when he hits a small maintenance room. He's landed on piles of clothes, food wrappers and other things he doesn't want to think about from the smell and he's facing a kid across the room, pressed into a corner and breathing raggedly.

It's a slim boy, maybe eighteen or nineteen if Derek had to guess, made younger on first glance by grime and gauntness. The boy's eyes dart to another access hatch near his thrown-out hand on the other side of the room and he's diving for it a second later.

Derek anticipates the move, lunges and grabs the boy up, folds arms around him, pinning his own to his sides. The boy kicks and squeals, a horrible panicked sound. Derek grimaces because the kid's heart is going way too fast, his breathing erratic. "Hey, calm the hell down!" Derek barks but an Alpha's order is useless on a panicked human. The boy is going to hurt himself or maybe stroke out of he keeps going so Derek does the only thing he can.

He secures the boy in just one arm, a little harder than two because the boy is slippery and desperate, but he manages long enough to open his med pocket and extract the tranq pen that's standard issue. He jabs the boy in the neck and presses the button. The boy jerks one last time, before he goes limp, heart returning to normal and breathing evening out.

"Christ, kid," Derek breathes. He clicks his comms back on to the sound of every single one of his beta's yelling at once, Sheriff's voice trying to be heard over the cacophony. "Hey!"

There's silence immediately.

"McCall, get your ass down here," Derek orders.

*

Through the access hatch from the maintenance room Derek had accidentally found himself in, there was another crawl space and a floor panel that brought them out just beyond the barricade and the operations doors. Derek and Scott muscled the kid through, the others picking their slow, careful way behind after Derek had rubbed a hand over the access panel's side wall to scent mark it so they wouldn't miss it in the dim.

Operations has a med bay attached and Derek points Scott in that direction with a jut of his chin and hands the boy off. One of the reasons Derek had taken Scott over a number of other transfer applicants was because he was a trained field medic and Derek's glad for that now. He turns back to the others when Scott disappears with the boy and his med kit. They're all looking warily around, probably expected to find a bunch of colonists holed up behind the barricade and Derek has to admit that he's surprised by the empty space himself.

"Jackson, Martin, secure operations. Boyd, get on the terminal and see if you can call up the colonist's PICs."

"Sarge?" Derek turns around to see Scott hovering behind him, looking a little pale. "There's something you should see."

Derek frowns but follows, doesn't like the way Scott's scent has changed or the confused edge to it. He feels his other wolves at his back, knows without looking that Erica and Isaac are at his shoulders.

Derek's not sure what he's expecting to see when he gets to the med bay. Possibly the boy having simply expired from all the excitement, that the one survivor of whatever the hell has happened that could give them some clue is gone, but Scott bypasses the beds and waves a hand at the back corner of the med bay.

Derek's not sure what he's looking at for a moment. There are four large specimen jars with pinkish fluid inside and what looks like giant, flesh colored spiders blobbing about. Derek hears Isaac swallow convulsively behind him and Erica crack her knuckles, a giveaway that she's unsettled. Derek approaches the jars, sure that the contents will start to _make sense_ if he gets closer.

"Gross!" Isaac whispers, leaning over Derek's shoulder, mouth turned down in distaste. "What the hell-?" He's reaching out a hand to one of the jars and before Derek can slap it down, the fleshy thing inside _lunges_ at the glass. Isaac lets out a shriek and Erica scuttles backwards, hissing.

Scott's standing off to the side, looking calm and holding a med tablet. His fingers are brushing over the surface, eyes scanning. "Hostile life forms, no other description. Apparently they were... oh god, this says they were _attached_ to people."

"You think the barricades were to try and keep these things out?" Erica asks, scraping her helmet off her head and dropping it on a nearby table. She undoes her hair so she can brush hands through it, quick motions like she's trying to rid herself of something crawling over her. Derek understands the compulsion.

"Maybe," Scott huffs but he looks dubious.

"What are you thinking?" Derek asks.

"Sarge, I just... it doesn't explain where all the people went. Even if..." Scott swallows hard then makes a face. "Even if these things _ate_ everyone and there were hundreds of them, there'd be evidence. There's just nothing, like the colonists were taken somewhere."

Derek's been thinking the same. He knows it's happened before, some newly colonized planet wiped clean, but that had always been unforeseen environmental factors and there was _always_ clues as to what had happened. Derek gets the impression that the operations area had become a sort of last stand, and even if the colonists were down to only a handful in number, there still should have been some kind of hint, maybe not to human senses but at least to the werewolf ones as to what went down.

Derek's troubled by the lack of people, by the melted hole in the floor and the flesh colored monsters that still strain against the glass of their containers like they know there's prey close.

"We'll have to wait for sleeping beauty here to wake up and tell us what the hell has been going on," Derek says, tapping a foot against the bed the boy's been slung across. Erica shrugs, undoes a canteen from her belt and uncaps it. Before Derek can stop her, she upends the contents over the boy's head.

The kid comes awake all at once, flailing and screeching. Scott makes a grab for him but he's fast for a human, darts sideways and skids around him, nearly falling. Derek snaps out a hand and snags the kid by the collar, the material gritty in his fingers and it tears away when the kid desperately lunges for the doorway. Isaac's in his way though and he just picks the kid up, his feet flailing and kicking.

"Quit it!" Derek yells, injecting as much of the Alpha power into his voice as he can. Sometimes it'll work on humans if there's enough behind it and it seems to now, the kid going slack in Isaac's grip. Isaac's looking over the kid's shoulder, bewildered. "That's better," Derek says gently, indicates that Isaac should lower him onto the tabletop just behind, legs dangling.

*

"He seems fine. He's a little malnourished but I'm pretty sure he's been living on candy and dehydrated food packets so that's to be expected." Scott is packing away his kit and looking at the boy with a concerned frown. "We have no idea what kind of trauma he's been through."

Derek waves Scott aside. He's never been known for his bedside manner in the corps, but his father had always told him that he had a way about him, something that urged people to follow, to obey. He's hoping that something can crack through the kid's current thousand mile stare. He moves to stand where Scott had been, tucks the end of his own sleeve over his hand and wipes the kid's face gently with the material. There are streaks through the dirt where Erica's water has tracked and there's pale skin and moles underneath the layer of grime.

"Wow, I wasn't sure there'd be a face under all this," Derek muses, continuing to gently clean the kid's face. There's some bruises and scrapes but Scott had scanned him and confirmed there was no broken bones, no internal damage. He's surprisingly healthy for an apparent sole survivor of a catastrophe which makes the whole situation all the stranger.

Boyd appears, holding the kid's tags and a data tablet. "I couldn't get a full name off these," he says, waggling them. "I don't know what this guy's been doing but the tags got pretty corrupted. I could get what I think is a _first_ name but I'm not sure anyone would be that mean to their own offspring."

Derek grunts and takes the tablet from Boyd's grip. He's sure Boyd is exaggerating but then he reads the name on the tablet and isn't sure he can even pronounce it. "How on earth do you say-?"

"Stiles."

Derek blinks for a second. The voice is rough from disuse, but insistent. "What?"

The kid's eyes finally seem to focus after a struggle and then he's looking right at Derek. "Everyone calls me Stiles. No one calls me by my real name... except my mom."

"Where's your mom now?"

"She's dead alright, can I go now?" Stiles bursts out, goes to jump down off the table but Derek cages him in with a hand on either side of Stiles' narrow hips. Scott's looking at him with a disapproving scowl like Derek bracketing Stiles in is the worst thing he could be doing, but Derek needs answers and he needs them now.

"Don't you think you'd be safer here with us? We're a trained were-unit."

"It won't matter," Stiles says.

*

Derek's hoping that getting Stiles to say a few words will open the floodgates, but the kid clams up again after his outburst, all large eyes and firmed down mouth. He seems the least tense around Scott so Derek assigns him babysitting duty and prods Scott to get _something_ out of Stiles.

Any intel is better than none at this point.

Derek is back out in the main operations area, hovering over Boyd who's scanning the complex for signs of life. Each colonist, like Stiles, has a Personal Identification Card that they're supposed to have on their person at all times so they can be found if there's an incident. Lydia, Jackson, Erica and Isaac all hover at the entry points, casting nervous glances at the med bay while Boyd runs a search.

"Sargent Hale, we're getting pretty damn tired of cooling our heels," Derek hears on his comms. That's Gerard Argent's voice and Derek grimaces.

"Mr Argent, we need to clear the area first and I'm not confident we have."

"Sorry, I got sick of him griping at me and figured you could have a turn," Sheriff says, sounding put-upon.

"And it's not even my birthday," Derek huffs.

"What are we looking at?"

"I'm not sure yet," Derek says and when Sheriff makes an impatient noise, he adds, "Honestly, I'm really _not sure_. We've found a single survivor out of what, forty or fifty families? And he's not talking."

There's a strained silence for a second and then a weirdly strangled noise, like Sheriff wanted to say something but stopped himself. Finally he clears his throat and says, "No evidence of what happened?"

"Nothing. They barricaded themselves in pretty well. There was pulse weapon fire and then... nothing."

"Hold up!" Boyd calls from his console. "I think I found 'em!"

Derek joins the others crowding around Boyd, shuffles Isaac and Erica out of his way so he can see what Boyd's looking at. "How many?"

"All of them, I think," Boyd says, sounding mystified. "Under the primary cooling towers, near the main heat exchangers."

"Sir," Derek says. He leans down and switches on his helmet camera so Sheriff can take a look. "Think you can find us a way there?"

"Probably easiest to circle outside the building and come to it through engineering."

"Alright, let's go," Derek says, shakes his head when he sees Scott emerge from the direction of the med bay pulling his gear back on. "Not you, stay here with the kid."

"He's eighteen," Scott says, waving a hand behind himself. "He's not really a kid."

"Then you stay here with the _young man_ ," Derek says, rolling his eyes. "Let us know if you get anything useful out of him."

Scott grumbles but retreats back down the corridor. Derek can hear the quiet murmur of Scott's voice when he reaches Stiles, reassuring and gentle. There's no response and Derek tries not to feel frustrated.

*

It's drizzling when they're outside. Being so close to the environmental processors, the weather on the ground can be unpredictable. Derek has never liked the rain particularly. It washes scents out, dulls everything down. He feels handicapped with one of his most valuable senses compromised but Erica gives him a grim little nod and grips her pulse rifle tighter when he looks back at her so Derek moves forward, feeling the others fan out at his back.

They skirt the complex quickly. It's a big place but whenever Derek doesn't have a human to worry about leaving behind, he makes the wolves double-time it. Boyd shouldn't be able to move as quickly as he does with the M56, no human could, but he bears it with ease and doesn't falter.

They reach a large set of blast doors on the other side and Sheriff lets him know they're at engineering. Derek waves Lydia forward again to run an override and when the doors slide open, Boyd is the first through with Erica at his hip, having reclaimed the motion detector. The other side of the complex is about as much of a labyrinth as the first part and they're having to rely heavily on Sheriff's guidance, Derek made edgy by the darkness and the pervading smell of damp that overrides everything else like the rain did outside.

When they reach the right area, Jackson tugs a small tablet free from Boyd's belt and holds it out, the small pinging noise indicating that they're close to the large grouping of PICs.

"Ugh, what the hell am I walking on?" Lydia complains and Derek's noticed it too, the metal floor covered in something spongy. When he looks down though he isn't any the wiser, only able to discern _dark_ and _slick_.

Derek puts a fist up, an indication for silence because he really doesn't like the look of what they're walking into. The walls and ceiling are also covered with the same weird substance the floors are. It looks like really unpleasant alien vegetation, a kind of fleshy creeping vine. He glances at Jackson who flicks his chin forward. They're in a narrow corridor with a blind corner at the end and Derek feels his hackles raise and his fangs elongate in response to the prospect of walking into the unknown, wolf part of him wary and uncertain.

"Hale," Chris Argent says on comms and Derek freezes, holds up a flat hand and the others stop dead. "You can't use your weapons down there."

"What?" Derek hisses, the others all making low sounds of dismay at the prospect. "Sheriff?"

"He's right," Sheriff says. "We were looking at the plans and you're standing under the primary heat exchangers. If you rupture the cooling system and it shuts down-"

"You just don't want to do that, alright," Chris interrupts and while Derek has had only the most basic of science educations, he can tell when someone is talking about kissing your ass goodbye in no uncertain terms.

"Fantastic," Derek groans. "You heard the man, sling 'em." Derek watches his squad unhook and unclip, piling their weapons off.

Boyd hesitates and when Derek glares at him, he rolls his eyes. "It'll take me ten minutes just to get unharnessed," he says and Derek holds out a hand until with a scowl Boyd hands over his ammo clip.

"We've gone into worse with less," Derek says, always mindful of the shifting mood of his pack. They're unsettled and getting edgier by the minute. This is not a normal military outfit. Derek knows he can lose control of the betas if they're pushed too far.

Derek moves forward. At the end of the corridor and around the corner is a larger space with what looks like a vent running up through the middle. There are stairs peeling off every which way and more of the wall and floor growths. The air is muggy and oppressive and Derek feels sweat spring up across his forehead and run down his nose from under his helmet.

"Sarge!" Derek winces when Scott yells into the comms.

"Dial down the volume, McCall, Christ," he swears. When he pauses Erica and Boyd move past him, Erica still holding the motion detector out and Derek tries not to let it get to him that other than tooth and claw, it's basically their only weapon.

"Stiles came around a little more and asked where you'd all gone. When I told him, he _freaked out_." Now Derek is listening, he can definitely hear someone yelling in the background. A steady stream of _get them out, tell them to get out of there_.

"You'd better sedate him again, he sounds like he's going to have a heart attack," Derek says. Lydia and Jackson brush by him, both making contact and Derek is a little reassured by it. Isaac pauses by his shoulder.

"Sarge, he's freaking _me_ out. I think you'd better get out of there. He's saying there are monsters."

"Monsters? What, McCall, I don't have time to-"

"Movement!" Erica barks. She's spinning in place, her face confused. "Multiple signals, all around."

"Is it the colonists?" Jackson asks. He's backed up against one of the walls and startles forward suddenly with a yelp. He spins and Derek can see that he'd bumped up against a hand attached to an arm, attached to a person that is attached to the _wall_ behind him.

Lydia gasps and darts around Jackson to reach what looks like a young woman. She puts a hand out, presses fingers to the woman's throat but even from where he's standing, Derek can't hear a heartbeat, can smell old blood. Lydia looks back at him with a grim little shake of her head. Further along, there's another man, then another woman, then three more men, all similarly fixed to the wall, all with bloodied torsos.

"What the hell?" Isaac says, voice almost a low whine.

That's when the walls start moving.

*

Big monstrous _creatures_ basically peel themselves away from the walls and the floors. The don't smell like anything except the pervading dampness and chemical underneath that and Derek can't determine individual heart beats so he's not too thrilled about what that says about their physiology.

Derek only realizes that Isaac is about six feet in the air when his boot connects with the back of Derek's head. Derek spins, grabs and _wrenches_ Isaac back down, can't really make out what grabbed him. Derek sees Erica out of the corner of his eye as she bares claws and launches herself at one of the moving figures. She slashes and there is the spray of something that must be blood but is a dirty yellow in color, then Erica is screaming, ripping her tac vest off because it's smoking.

"Don't cut them!" Derek yells when he sees what's happened and the dots connect in his brain, the melted floor and Erica's uniform disintegrating making a bad kind of sense. He's faced creatures back home with caustic blood before, a primitive but effective defense mechanism. Something rears up right by his shoulder and Derek punches it, satisfied when what feels like an insect's carapace crunches underneath his fist.

"Hale..out...there!" someone is yelling in Derek's comms. He's pretty sure it's Sheriff and he'd love to oblige but there's only one way in to what Derek now realizes is a killing jar and the corridor entrance looks thick with dark shapes, trying to contain them. He's hoping these creatures are used to dealing only with humans, that they haven't encountered werewolves before because that's their only chance for fighting their way out, their strength being underestimated.

"Marines, we are leaving!" Derek yells. He sees Jackson toss Erica over his shoulder and Isaac's already making his way towards the exit, picking up and throwing one of the creatures out of his way. There are a lot of the monsters at the corridor they have to pass through and Derek's not sure they'll be able to cut through without cutting _them_.

"I'll make a door!" Boyd calls, and before Derek can stop him, he's yanked a spare ammo clip from his belt and clicked it home.

"Boyd, no!" Derek yells, but it's too late. Boyd fires, the M56 deafening in the enclosed space. They're all far enough back that they're not hit with the spray and the shooting has the desired effect, the creatures scattering, scuttling up the opposite wall and around. Derek doesn't waste any time, racing for the temporarily open corridor, the others close on his heels.

The creatures, _aliens_ Derek mentally amends, regroup quickly and pour out behind them. The wolves are fast but he doesn't think they're fast enough and they'll be overwhelmed before they hit the blast doors to the outside.

Except, when they reach the end of the corridor, there's the shuttle's APC sitting waiting for them, Chris Argent hanging out of the side hatch and waving urgently. Derek pauses long enough to usher the others past him and then follows. Just when he reaches the APC's hatch, something grabs onto the back of his tac vest. Chris levels a hand gun over his shoulder and shoots, there's a screech and then he's released. Chris swears and flails backwards, cupping his arm and Derek can already see raised, red bubbled flesh breaking out along his skin just from the few droplets of alien blood that made contact with Chris’ skin.

Sheriff's there the next moment, yanking Chris out of the way and helping Derek close the hatch. Just before they do, what Derek can only think of as a segmented tail flicks through the narrow gap and catches Sheriff in the temple. Sheriff slumps back and Derek catches him one-armed, yanking the hatch closed with the other.

"Thought you guys could use a lift!" Allison calls jovially from the driver's seat. Gerard Argent is also inside, looking imperious as the others slump down. Allison turns the APC around as fast as she can and there's the sound of crunching under the wheels and bodies hitting the side and then they're through the blast doors and outside, skirting the complex.

Allison slows to a stop when they're about halfway around, the inside cabin almost choked with the fumes from Erica's still smoking clothes. Derek checks the view window out the back but nothing's followed them outside so he cracks open the side hatch. Allison's already retrieved the first aid kit from a lockbox under the driver's seat and is hunkered in front of her father, giving him a shot for the obvious pain.

Derek checks Sheriff after a quick once-over of his pack. Erica is already healing, biting down on Jackson's hand while skin along her throat and across her chest slowly knits together again, blood growing sluggish and then trailing off. Jackson is putting up with the abuse more graciously than usual as Lydia hovers over them, looking anxious. Isaac has a few scratches from being grabbed that are already mostly gone and Boyd is unclipping himself from his harness, grumbling.

"Is he-?" Isaac asks, flicking his chin at Sheriff and looking worried.

"Unconscious," Derek says, holding a hand against the sluggishly leaking wound on Sheriff's forehead. Allison tosses him a roll of patch tape from the med kit and Derek nods and makes himself busy binding Sheriff's cut. Isaac still looks rattled so Derek takes a moment to reach out and rub a consoling hand across his throat. Isaac leans into the touch for a moment, before he seems to rally and goes to help Boyd out of the rest of his gear.

"What the hell were those things?" Erica groans, sitting up. 

"I don't know," Derek says, casts a narrow-eyed look at Chris. "Did you-?"

"I know you probably won't believe me, but I had no idea," Chris says. "I was hoping for a downed transmitter, same as you."

"Why _should_ we believe you?" Lydia snarls, curled against Jackson's side and protectively over Erica.

"You think I'd let my daughter walk into something like this?" Chris asks and Lydia stares him down for a moment, before she pulls a _fair enough_ face.

"Sarge?" Lydia says, her focus swinging to him, and Derek realizes all attention has turned his way, waiting for a plan.

"I say we dust off, nuke the site from orbit," Derek says, grim. "I'm only going to be happy when this is nothing more than a debris field."

"What a goddamned minute!" Gerard splutters. "This is a multi _billion_ dollar facility. You can't make that kind of decision!"

"I can, sir," Derek says, standing up to his full height. "This is currently a military operation and as the ranking officer-"

"Ranking officer?" Gerard spits, sounding disgusted.

"Yes, sir, _ranking_ officer. It's my decision as to whether we abandon a compromised location and what to do with it to ensure there are no further casualties. There's massive loss of life here and I know that doesn't matter as much to you as the hit to your bottom line, but it does to me. We just got our asses handed to us in there. I'm willing to call this one for the aliens, take our single survivor and execute a prudent retreat."

"You are going to regret this," Gerard promises gamely.

Derek ignores the threat he can't do anything about and turns to Allison. "Is the Synthetic with the shuttle?"

"Yes."

"Get on comms, tell him to prep the ship for dust off in ten, then contact McCall and get him to grab the kid and anything else he can carry and meet us at the landing bay as soon as possible."

"Yes, sir."

*

When the APC rounds the last corner of the complex, Derek has to shield his eyes against the bright glow of fire where the shuttle was standing. "Son of a bitch!" he hears Allison swear from the driver's seat as she yanks the APC to a halt.

Derek's the first out of the APC, barking Scott's name into the comms. He catches sight of Scott and Stiles before he can respond though, standing hunched against the side of the complex. Scott has a hand on Stiles' shoulder and the kid's watching the shuttle burn with eyes made black pits by the shadows.

Derek jogs over to them, shielding the side of his face with a hand from the warmth as he goes. "What the hell happened?" he calls as he gets closer.

"We don't know. It was burning when we got out here. Daehler radioed to say we could board but he was cut off."

"We've got some injuries in the APC, go," Derek instructs. Scott hesitates, glancing at Stiles who seems transfixed but Derek gives him a shove and he scuttles towards the APC, dodging around Isaac and Boyd who have tumbled out in the meantime.

"I guess we're not leaving."

"I'm sorry," Derek says.

Stiles seems to come back to himself, offers a humorless little grin. "It's okay. I figured..." he trails off, sounding resigned, doesn't finish his thought. He shakes himself a little, looks at Derek straight in the eye for the first time since his outburst about his mother. "We should go back inside. It'll be dark soon."

"Is that bad?" Derek asks and Stiles' rictus grin gets a little wider, a little more unsettling.

"Haven't you ever seen a horror movie? Monsters mostly come out at night." He's turned away so all Derek can see is his profile, outlined in firelight when he repeats, "Mostly."

*

Derek sends Stiles back inside the complex with Isaac and Boyd before he sees about unloading Sheriff from the APC. There's a collapsible stretcher that they unfold and Jackson and Scott grimly lug Sheriff out on it. "It's going to be a bitch to maneuver him through the barricade and the vents," Jackson points out.

"Cut a hole through," Derek instructs, knowing there's no other way. "We'll patch and fortify when we're settled." He sends Lydia and Erica to the shuttle to put the fire out and see if they can salvage anything useful from the wreckage. Gerard strides by him, treating him to a narrowed glare and then Allison is there with Chris, his good arm slung across her shoulders, made unsteady by the painkillers.

"I've got him," she says when Derek moves to take Chris' weight from her. There's something that rankles Derek about Gerard Argent, but he believes Chris, that he had no idea what they were walking into. Gerard has been very careful not to make the same denials around the werewolves and Derek thinks maybe a confrontation is in order so he can tell if the man will try to lie about how much he knows.

Derek nods and steps aside for Allison, then makes his way to the shuttle wreckage, hoping they're left with something to work with.

*

Derek's only just unloading his haul onto the floor of operations when Scott grabs his sleeve and tugs him towards med bay. "Sarge! It's-!"

Derek's heart feels like it drops into his feet. He's tugging free of Scott and moving past him, fearing the worst, but when he gets to med bay it's to see Sheriff laid out on the spare cot and Stiles perched on an overturned crate pulled up right next to it, holding his hand.

"What's going on?" Derek asks slowly out of the corner of his mouth, confused.

"I was trying to tell you," Scott grunts. "Boyd couldn't read Stiles' last name off his PIC and I didn't think to ask him what with everything happening. It's... I mean, it's _Stilinski_."

"You're shitting me," Derek says, astounded.

"Did you know the lieutenant had a kid? Did you know he had a kid _here_?"

"No, of course not. He wouldn't..." Derek sighs, rubs a hand over his face. "He pushed for this assignment. He had to come and make sure Stiles was okay himself, of course he did." Derek can understand the compulsion. Being a born werewolf, he's always had a strong sense of family, of pack. Sheriff was the first human he'd willingly followed because he'd always gotten a sense that the man was the same.

"I checked the manifests. The last colonist transport was ten years ago. He hasn't seen Stiles in the flesh in that long, maybe longer with the stasis jag in between."

Derek can't imagine it. He can't even fathom going a week without seeing his pack, those he's bonded himself to. He'd lost his family early, his sister more recently. When they were alive though, he'd never been separated from them, he couldn't be.

"I mean, I knew he was married. He always wore that ring although... oh no." Scott's aghast expression triggers a memory in Derek's own mind.

_She's dead alright, can I go now?_

"Why is the weird kid holding the lieutenant's hand?" Jackson asks from behind them. Derek turns around only long enough to cuff Jackson on the back of the head.

"You know, I might not be a werewolf, but I'm not deaf either," Stiles says, throwing them an unimpressed look over his shoulder. Jackson snorts, always unapologetic and disappears back the way he'd come. Scott goes to move forward but Derek pats him on the shoulder.

"Check on Argent," he instructs and Scott looks torn, but goes. Derek huffs because Scott is proving to be exactly like Derek was expecting, competent but also quick to get attached to any strays he happens upon.

Derek moves into the med bay properly, sits down on the empty cot set next to the wall. "How long has it been since you saw him?" he asks gently. He's expecting Stiles to maybe shut down again or tell Derek unceremoniously that he can shove it, but Stiles surprises him by answering.

"We vidded in between but... twelve years. Two in stasis and we've been on planet for ten."

"Your parents were separated?"

"By distance, yes, but not... mom couldn't turn down the colony position, it would have paid enough to let dad retire from service. We were going to settle on Acheron so I could go to school. They were doing it for me. They kept telling me it wasn't but... I mean, I knew..." Stiles chews at his lower lip for a moment, then looks up at Derek with a wan expression. "Dad was offered a security position last year on planet and he turned it down, said he would've gone crazy. I was so _angry_ at him, that he was separating us. I didn't return his calls for the last six months but if he'd been here-"

"Hey, don't beat yourself up."

"He never mentioned me?"

Derek thinks about lying for a second, but then discards the impulse. "No."

"He must've been angry too," Stiles says. "But if he'd been here, he'd be dead."

*

"What am I looking at?" Derek asks, joining Chris Argent at the view window on the side of operations when the man had come to fetch him with a grim expression. They're overlooking the desolate landscape and the closest of the environmental processors.

"Wait for it," Chris says. He's more alert, having refused additional painkillers despite Allison's protests. Derek can practically _feel_ the pain radiating off the man but it's not his place to try and put his foot down and Chris is bearing it better than Derek could have expected. He nudges up against Chris, as subtle as he can be, finds the curl of pain and draws it into himself. The tenseness bleeds out of Chris' shoulders.

"I know what you're doing," he says, glancing at Derek out of the corner of his eye.

"Sorry," Derek says but Chris huffs.

"Don't apologize, I wasn't complaining. Look, there!" Chris points out the viewing window where a column of greenish flame is jetting from the top of the processor.

"What is that?"

"Emergency venting," Lydia says from behind them. Chris looks surprised but Derek isn't. He's always wondered how he ended up with Lydia, thinks it mostly has to do with Jackson although she could have easily ended up in Intel, maybe been the first werewolf that got a decent rank. Derek knows she's smart enough. "The blast radius will be about eighteen miles."

"Would the complex be protection in any way?" Derek asks, not really hopeful.

"In a little over seventy two hours we might as well be sitting behind a piece of paper for all the protection it'll offer," Lydia says.

"How do you know all this?" Chris asks, blinking.

Lydia waggles the tablet in her hand. "I skimmed the schematics, did the math," she says with a shrug.

"How long before we're declared overdue can we expect a rescue?"

"Seventeen days," Derek says with a grimace.

The others have gathered and Jackson throws his hands up. "We're not going to last seventeen _hours_ with those monsters running around."

"That _human_ survived longer than that," Derek says, pointing towards the med bay.

"Maybe he should be the Alpha," Jackson spits and Derek growls, eyes flooding red and fangs elongating. Jackson waivers before finally curling into himself, submitting.

"Look, we need a plan. Waiting for rescue is out so I need realistic ideas."

"We need to get the other drop ship from the Beacon. I could remote pilot it down but the transmitter was on the other shuttle and it's trashed," Allison says.

"There's a colony transmitter," Lydia says, holding the tablet out and tapping a nail at a marked section. She frowns when she curls the tablet back to herself. "The uplink terminal is in engineering though which I don't think anyone is keen to revisit."

"I could patch in manually," Allison says, hunching close to Lydia so she can see the schematic. "There's a ventilation duct that runs from here down to the transmitter."

"We don't know where those things are, there could be a whole bunch of them camped out in there," Isaac says, grimacing.

"Sarge, that kid survived a long time by himself, maybe _because_ he was by himself. I could-"

"Don't even think about it," Chris interrupts.

"Dad, now is not the time to play the protective parent card."

"I'm not playing the protective parent card." When Allison eyes him, Chris holds up his hands, says, "Fine, okay, maybe a little bit, but I'm also being practical. I'm pretty rusty but I could remote a drop-ship onto a planet. I'm not sure I could get one back up to an orbiting vessel and dock it if we don't have time to program the autopilot first."

"What are you saying?"

"I'm saying I'll go. If something happens to me you can make a run for the transmitter with force instead of stealth and hope for the best."

"I can't send you out there alone," Derek says. "Take Lydia and Jackson with you."

Chris looks like he's going to protest, but then huffs and glances down at his injured arm, acknowledging that he's more than likely going to need help.

"Fantastic," Jackson grunts, not sounding exactly pleased about the prospect.

*

Stiles is still sitting by Sheriff's side, looking pale and pensive when Derek goes back to the med bay. Scott gives Derek a tight smile and retreats as Derek approaches Stiles. He's not sure why, but he no longer sees Stiles as just a survivor but also as someone he wants to protect. He supposes it's that familial instinct, knowing Stiles is Sheriff's and therefore automatically an extension of his pack.

"You okay?" Derek asks, winces a little because it's probably the dumbest question he could ask.

"I'm stuck on a planet with a bunch of aliens with acid for blood who want to turn my body into an incubator their cute little babies can chew their way out of," Stiles says, turns his head slowly so he can look at Derek. "Yeah, peachy, you?"

"Sorry."

"Nah, it's fine," Stiles says. "Not your fault right? You weren't the one that nagged their mom to go out to that wreck because you were _bored_."

"Is that what happened?"

"There was a call in to go check out the distress beacon. My mom thought it was too dangerous, was arguing against _any_ of the colonists going out there but I bugged her until she volunteered herself." Stiles' eyes skate to the specimen jars in the corner. "She was the first one who... they killed her getting it off."

"You couldn't have known," Derek offers gently, although he's sure Stiles isn't interested in his platitudes.

"I was being a brat about dad, working her last nerve. She was saying that we should just leave, that it wasn't worth it. They were doing it all for me and I was an ungrateful-"

"Stiles."

"Yeah, sure, I couldn't have known, but in that derelict ship there were all these... they looked like pods, like these upright slimy eggs. She told me not to go near them but I was curious. When one opened, my mom knocked me out of the way and it..." Stiles' hands come up, grasping at the air and then flutter down to fold over his face. He hunches, forehead landing by Sheriff's hip and his whole body shudders.

"Her last act was saving your life," Derek says. "I'm going to make sure she didn't do it in vain."

"Do people really talk like that, or only mega-hot werewolf marines?" Stiles says, voice muffled where his face is pressed into Sheriff's bed.

"Mega hot?" Derek chokes out.

Stiles turns his face so he can look at Derek with one eye. "Don't get a big head. I'm pretty sure I'm in shock so you can't hold me to anything I say. I'll get Scott to give me a medical note backing me up."

Derek reaches out, rubs a hand over Stiles' head and he ducks away but he can't really hold onto the scowl he's trying for. Scott reappears, hesitates in the doorway. "Everything alright?"

"Yeah," Stiles huffs.

"I have to check on-" Scott gestures at Sheriff and Derek nods, moves out of the way, curls a hand in Stiles' shirt to yank him after.

"Come get some food. You can come straight back when Scott's finished."

Stiles hesitates, but then nods stiffly and follows at Derek's heels.

*

Derek breaks into a run when he hears the sounds of shouting from the main operations area. "What the hell is going on?" he barks when he finds Erica, Isaac and Boyd clustered around a monitor. Gerard is watching them with a look of distaste on his face and Allison is sitting off to the side, clutching a small cup of coffee.

"Allison and Lydia retrieved the two smart guns from the drop ship wreckage. We set them up on the other side of the barricade before we repaired it and Lydia patched them into one of the motion sensors before she went with Chris. They activated," Erica explains.

Derek shoulders the clustered wolves out of his way, sees Stiles wedge his skinny frame in sideways so he can see as well. "What am I looking at?" Derek asks. All he can make out is smoke, masses of movement and flashes of light.

"They must be wall to wall out there," Boyd says, sounding more anxious than he ever has. Set up next to the monitor is the remote systems pack for the smart guns. There are two counters for the ammo each gun holds and they're racing down, getting closer and closer to zero.

"Left gun almost dry," Isaac says right before the low ammo alarm blares and then one of the counters clicks to zero. The other is still up around one hundred but it blips down to eighty, then to sixty as they watch. The low ammo warning kicks up and at twelve rounds the counter stops dropping and there's silence.

They all hold their breath but nothing else happens for a minute and then two. "They could just walk right up and knock next time," Boyd says.

"Can they get through the floor like we did?" Derek asks.

"We patched it and also barricaded the storage room's entrance with some of the drop ship wreckage so they'll have to find another way to come at us," Isaac says.

"You trapped us in here?" Stiles asks, frowning.

"We figured we'd be following Chris and the others through the ventilation duct, that the aliens would try and come at us the same way they'd gotten to the colonists so that was where we needed to put the most protection," Erica says.

Stiles pulls a face and moves away a little. Derek follows, concerned. "What?"

"You can't move a stretcher through the ventilation ducts. There's parts where you have to go up and down access ladders."

"Your dad will have come around by then," Derek says. "Even if he doesn't, one of us will carry him. We're pretty strong."

"I guess," Stiles allows. He's still looking a little shaky and Derek sighs, then does something he'll probably later regret.

"Let me introduce you to a friend of mine," Derek says, hefts his pulse rifle and Stiles' eyes go round and keen. "M-41A 10mm pulse-rifle, over and under with a 30mm pump-action grenade launcher."

"Are you serious?" Stiles breathes, accepts the pulse rifle with careful hands when Derek hands it over to test the weight.

"Yeah Derek. Are you serious? That kid will just end up shooting his dick off," Isaac says, then makes a horrified face. "Or mine."

"Stow it Lahey," Derek says as Stiles hefts the gun. He's clumsy at first with tension, but gets more confident and Derek loops arms over his shoulders and shows him where to place his hands, how to tuck it into his shoulder so it won't kick. The pulse rifle is heavy and awkward, built for power and not for sleekness but Stiles' lanky frame, long arms and large hands suit it. He's able to get a comfortable grip and then he's looking up and back at Derek.

"So, how do I _not_ shoot my dick off?" he asks with a reckless grin that Derek hasn't seen before but definitely likes.

*

Stiles goes back to the med bay with one of the spare pulse rifles held tight against his chest, looking a little happier. Scott passes him in the corridor and then he's looking at Derek with raised eyebrows. Derek just shrugs. He knows what it's like to feel powerless and Stiles' whole demeanor had changed when he had a weapon in hand..

"How's Sheriff?"

"Stable," Scott huffs. "It's just a matter of time now."

*

Derek sends Isaac and Erica to get some sleep while Scott and Boyd walk the perimeter corridors outside operations. Derek checks in on the med bay, feels real panic for a few seconds when he can't immediately see Stiles before he notices the glow of a heat light under Sheriff's cot, the corner of a blanket poking out and the toe of a sneakered foot. He can't imagine it's comfortable on the floor, but exhaustion makes a feather bed of any surface and there's the sound of gentle snoring from underneath.

Derek walks the corridors himself that ring operations, puts a hand to Boyd and then Scott as he passes them, finds Erica and Isaac curled together in a small maintenance alcove. They chose a spot they weren't going to be boxed in and also where both Scott and Boyd would have to pass them. Derek looks at his watch, figures he can give them another hour before he switches them out with Scott and Boyd who are starting to look ragged themselves.

Derek's back in operations and looking at a bank of darkened surveillance monitors with a hand on Allison to keep her from tipping all the way out of an uncomfortable looking chair while she sleeps with a frown on his face before it registers what's wrong.

Gerard's gone.

"McCall, Boyd, you seen Gerard come by you?" he asks quickly. Allison blinks awake at his voice and looks around blearily.

"No Sarge," they both say almost in unison and then Derek sees it, sitting shoved amongst their paltry pile of supplies, the pulse rifle he'd given to Stiles and he knew Stiles had taken to the med bay with him.

"Son of a bitch," Derek snarls. "Med bay, now!"

Just as Derek is running for the med bay the fire alarm goes off and Derek puts on a burst of speed, Allison's boots clanging gamely behind him. Derek hits the med bay door that they'd been leaving open but is now closed, access key pad to the side of it dismantled.

There's a viewing window to the side of the door and Derek moves to it, can see the sprinklers have activated in the room and Stiles is huddled, sodden and frantic, over Sheriff in the middle of the room. Scott hits the window next to Derek, Boyd right after him with Erica and Isaac on his heels, both pulling on their tac gear.

"Derek, look!" Scott says, alarmed and Derek follows the finger he's jabbing, sees the specimen jars rolling empty on the floor.

"Stiles!" Derek yells, thumping the glass and Stiles looks up at him right as something drops from the ceiling onto his shoulder. Stiles cries out and topples sideways off the bed and out of sight.

"Shoot the glass!" Allison yells and Derek backs up, transforming as Boyd and Scott raise their rifles and do that. The glass splinters, doesn't break but Derek ignores that, just runs at it and smashes through, the wolves and Allison hurtling in right after him.

One of the parasites leaps at Erica and she turns and splits it in half with a swipe of her claws, roaring. Derek skids in sideways and sees Stiles on his back with an arm up between himself and the other parasite that's got a long, segmented tail wrapped around his throat, jointed legs frantically scrabbling for his face.

Derek leaps over to him, unsheathes his claws and sinks them in when he grabs the parasite by the body, unmindful of the way the caustic blood burns away the skin of his fingers. Boyd's there as well, shoving in behind Stiles so he can pry the curled tail from around Stiles' neck.

"Isaac!" Derek bellows and he sees Isaac out of the corner of his eye raise his pulse rifle and then Derek and Boyd have the parasite free. It's _strong_ and Derek knows they won't be able to hold it for long. He and Boyd fling it towards a corner of the med bay and there's the short, sharp report of Isaac blowing it to pieces.

Stiles is gasping, still clawing weakly at his neck, a ring of red around his throat that'll turn black and blue in a day or so. Derek shuffles Boyd aside so he can grip Stiles to him, put a hand to his chest and help him breath. Stiles' feet skid on the floor and his body bows up and Derek keeps murmuring to him, a string of nonsense that finally gets Stiles to stop shaking and slump into the curve of Derek's body.

The others hover uncertainly, Scott checking over Sheriff when Stiles croaks something out.

"Stiles, what?" Derek says gently.

"Gerard," Stiles manages, raw voiced. "It was Gerard."

*

Stiles is sitting on the center table in operations, a pile of dejected limbs in somebody else's too-big clothes, all Erica could find in a pinch. He looks up long enough to ask, not for the first time in the last hour, "Is my dad-?"

"He's okay," Derek says. Sheriff is on one of the other tables with a blanket under him and Isaac's balled up jacket propping his head up. It'd made Derek's skin crawl to even think about having _anyone_ out of his sight since they don’t know where Gerard has gotten to.

"Just what did he think he was doing?" Erica asks as Scott nudges up against her, handing over a protein bar that she unwraps without enthusiasm.

"He was asking about the parasites. From the logs he had a look at the records that the colonists had made. He was figuring out a way to recoup his losses," Scott says. "A way to smuggle one or two of these monsters past quarantine back home."

"We'd know though," Isaac says, picking his head up out of his hand.

"He'd have to have planned to sabotage our stasis pods on the way home, jettison our bodies. He could’ve kept Stiles and the Lieutenant frozen and make up any story he liked. The Argents own the company which owns the supply station we use on the way home. No one would have argued with him."

"Where is he?" Boyd asks.

"Probably halfway down to the transmitter already. I'm _really_ glad you sent Chris down with Lydia and Jackson," Scott says, huffing.

"I don't think my dad would-" Allison starts to say and that's when the power in operations dies.

"Did they cut the power?" Scott hisses as Derek rises, alert.

"Stiles," Derek hisses, but Stiles is already up and pressed into his side, gripping the pulse rifle he hasn't let out of his grip since the med lab. "Boyd, you and McCall take Sheriff, go now. I don't give a damn if Chris isn't ready for us. Allison, you go with them."

No one argues with him. Boyd moves over to Sheriff, lifts him easily in a fireman's carry, lets Scott check him over quickly and then they move out. Before they disappear, Derek grasps Stiles by the shirt and shoves him towards Scott. "Take him," he orders.

Stiles twists out of his grip though, says, "No way."

"Stiles," Derek says but Stiles is shaking his head and nudging back into his side.

"You're going to buy them some time, right? I'm staying with you so you don't do something stupid." Derek growls but Erica and Isaac are looking at Stiles with grim little grins on their faces, like they approve.

"Movement," Erica says as the shrill sound of the tracker starts.

"Keep the way clear between us and the ventilation duct. It's our only way out," Derek says.

"Maybe you should have shown me how to use the grenade launcher on this thing," Stiles huffs, breath warm against the exposed curve of Derek's neck. He has to fight the almost overwhelming urge to just pick Stiles up and run with him. If the aliens are coming in force, they have to thin the ranks a little, enough that when they make a run for the transmitter tower, they won't get overwhelmed.

"You'd blow off more than just your dick with that," Derek grunts back and Stiles lets out a small, almost hysterical curl of laughter.

"Guess so."

"Here," Derek says, slings his pulse rifle onto his back and tugs his own military tags free of his neck, yanks them over his head and drops them over Stiles' own. Stiles picks the tags up off his chest for a moment, squints at them in the dim, emergency lighting.

"Does this mean we're going steady? I'm not sure I'm ready for anything so serious," Stiles says, smirking.

"It _means_ I can find you," Derek says, holding up a small tracking device hooked to his tac vest. "Just... don't get lost."

The acoustic ceiling near the operations doorway suddenly bows downwards like there's a great weight on it, then tiles break free and a nightmare rush of the aliens pours out.

*

The attack is spectacular in its ferocity. Derek has never faced an enemy so unmindful of its own mortality. He knows these creatures will keep coming to the very last one, not retreating when the odds swing against them. They must have been hive minded to a degree and _something_ is laying the eggs so Derek figures there is a huge, ugly ass queen alien somewhere but he can’t worry about that now. All he has time for is shooting or slashing anything that gets too close and keeping Stiles with him.

"Isaac, Erica!" Derek yells, giving up the urge to call them by last names like he's expected to. This is survival, this is _pack_ and everything else falls away in the face of that. Isaac and Erica retreat towards the ventilation duct entrance and Isaac hooks Stiles to drag him after as he passes. Stiles protests, but Derek also gives him a shove, doesn't give him a choice about arguing.

Live aliens scramble over dead ones, keep on coming. Derek knows he will have to move back to the duct, hopes pulling the covering closed and welding it will hold them for long enough and if they follow, they’ll have to do it one by one. He sets off a grenade, punches a hole in their advance and then spins and follows where the wolves and Stiles have gone.

Derek is quick-timing it through the duct when he reaches a junction with three paths and doesn’t know which direction to take. Suddenly a hand is grabbing his tac vest and tugging and Derek growls in frustration at Stiles who’s lingered behind.

"You'd totally get lost and I know a quicker way," Stiles says.

"You sure?"

"I was living in these ducts until you guys got here, believe me," Stiles says, eyes wide and white in his determined face and Derek just nods at him.

Stiles is fast through the ducts, nimble with practice. He warns Derek off spots that would see him plummeting otherwise and never hesitates, taking twists and turns that leave Derek reeling, unable to track by scent because of metal and artificial air. They make a left and almost crash straight into Isaac and Erica who had obviously got turned around and are relieved to see them.

Derek starts thinking, prematurely it turns out, that they're going to make it. He's so sure that he lets Stiles range a little too far ahead and Stiles mustn't know this end of the complex quite well enough because his head is turned to check on the wolves behind him when he steps off the main duct into a vertical shaft. He yelps, catches the edge for a second but then he's gone.

"Stiles!" Derek cries, scrambles forward, shunting Isaac and Erica out of the way. He lands on his belly, arms over the edge but he can't see anything, just a connecting duct curving away and down. "Stiles!"

"Derek!" he hears faintly from far below, feels a cold wash of relief.

"You two get to the ship. I'll-" Derek starts but Erica catches him by the vest, yanks him back.

"You don't know what's down there!"

"Stiles is down there."

"Find him with this," Erica snaps, patting Derek down and coming up with the tracking device. "Don't throw yourself head first into god knows what."

"Alright," Derek snarls. He yells down the shaft, "Stay exactly where you are, we're coming to you!" Derek's not sure if Stiles hears him, but he has to hope he does.

The ventilation duct ends and they find themselves on a platform overlooking the transmitter. Allison and Chris are both waving at them frantically and Derek jumps down to them. "How much time do we have?" he demands as Lydia appears beside him.

"Plenty. About half an hour give or take until it's too late to reach minimum safe distance," she supplies.

"I have to go back in for Stiles," Derek says.

"Well, you've got twenty eight minutes before we dust off and leave you behind," Chris says, offering Derek his hand. Derek takes it, shakes and offers a grim smile.

"You'd better," he says. Chris doesn't ask about Gerard and Derek doesn't spot him so knows he must have been caught by one of the aliens. There's a tight kind of pain in Chris' eyes, but also grim acceptance and Derek finds himself respecting the hell out of the guy.

He sheds himself of everything that will slow him down, makes it an order for his betas to stay with the shuttle when they look like they're going to follow him, then he's making his way back into the complex, tracking device held tightly in one fist.

*

A monster is holding Stiles captive, but it isn't an alien.

"Look who dropped in on me when I thought I was never going to find my way out of this goddamned place," Gerard says, holding Stiles with one arm around his neck and a gun pressed firmly to his temple with the other. Derek snarls, teeth elongating as Stiles' panicked eyes meet his own.

"Let him go," Derek snarls, words clumsy around his teeth.

"Why would I do that? You'll bite out my throat as soon as I do. He's my only leverage right now and I think I'll hang onto him until we reach home."

"I'm not letting you on the ship. You're going to stay right here with the other monsters."

"I found something else interesting," Gerard says, steps back and around something that looks like an oversized egg standing on one end, dark and slimy. Gerard changes his grip on Stiles, forces him forward and down until his face is inches from the surface of the egg. The egg pulses like it can sense something is there and Stiles make a strangled noise of real fear.

"You have my word you'll get safe passage. Just let him go."

"You'll forgive me if I don't trust the word of a _werewolf_ ," Gerard spits. "I think what you'll do is agree for my son to ferry me, Stiles here and my granddaughter up to the Beacon before we send it back for you and your pack."

"There isn't _time_ for that," Derek says, outraged.

"You'll just have to hope there is, because that is your only option if you don't want Stiles here to be traveling home with a nice little hitchhiker."

"Gerard-" Derek starts to say, starts to _warn_ actually because as they're talking a nightmarish silhouette unfolds itself out of the wall. Its large, segmented arms come down over Gerard, pick him up like he weighs nothing. He lets go of Stiles in his surprise. Stiles stumbles forward into Derek, who lifts him like he weighs nothing and _runs_ , not even bothering to look back at what happens to Gerard.

*

Derek knows they're late getting back to the shuttle, knows it shouldn't still be there but it is, waiting on them with Isaac and Scott hanging out of the access hatch. "Get inside!" Derek barks as he hands Stiles up to Scott and then scrambles after.

It's close, possibly too close because just as they take off, there's a muffled _whump_ and then a flash of light that's too bright to look at. Derek makes sure everyone's strapped down before he dives for his own seat, right as the shockwave hits them and they're tossed around like a can in the ocean. The ride smooths out, the light fades and Allison's voice on the intercom says, "It's okay, we're clear."

Sheriff's awake when they dock with the Beacon, holding Stiles to him like he's never going to let him go, which Derek doesn't blame him for. As he passes them, Sheriff throws out a hand and grips Derek's sleeve. He doesn't have to say anything, his face full of apology and gratitude and Derek just nods at him and is let go when he does.

*

Derek's dithering about getting into his stasis pod like he always does, one of the last to go down when Stiles pads up behind him. Derek turns to see him approach, wearing an oversized shirt and boxers with vulnerable bare feet, toes curling against the cold of the floor.

"In case I didn't say it before, thanks for saving my ass, like, multiple times," Stiles says, rubbing at the back of his head.

"It's okay. It's my job," Derek says, smiles when Stiles rolls his eyes.

"I'm pretty sure there was some above and beyond-ing going on."

"If I'd left your skinny butt behind I would have had to have answered to Sheriff," Derek says, makes a show of shuddering and pulling a face and it's Stiles' turn to smile.

"Yeah, he's pretty scary," Stiles agrees, looking back at the pod that holds his father, already locked away and peaceful although he’d vehemently protested about going down before his son. "So, we're going to sleep all the way home, right?"

"Yep," Derek sighs, knows he sounds as reluctant as he feels. No one really understands how hard it is for him to go down when his pack is so vulnerable, but the way that Stiles is looking back at his father and chewing his lip, maybe for once someone does. "We could stay up for a little while though?" Derek offers.

"Yeah?" Stiles says, looking relieved. "Maybe just until we can't see the debris field anymore?"

"Sure," Derek says.

"You got a deck of cards?" Stiles asks and Derek raises his eyebrows and then slings an arm around Stiles, tugs him into his side. Stiles goes, only grumbling a little as Derek messes a hand through Stiles' short hair.

The ship's systems hum as his pack sleeps and he and Stiles stay up, keeping watch.

Just for a little while.

**Author's Note:**

> Written for the Teen Wolf Crossover/Fusion Big Bang. Thank you to my wonderful artist mific.
> 
> A fusion fic with Aliens - no prior knowledge is required.
> 
> Come say hi on [tumblr](http://kellifer-k.tumblr.com/)

**Works inspired by this one:**

  * [Art for "only way to be sure"](https://archiveofourown.org/works/779477) by [mific](https://archiveofourown.org/users/mific/pseuds/mific)
  * [[Podfic of] only way to be sure](https://archiveofourown.org/works/993975) by [Podcath](https://archiveofourown.org/users/Podcath/pseuds/Podcath)
  * [Be Kind](https://archiveofourown.org/works/1598981) by [LadyDrace](https://archiveofourown.org/users/LadyDrace/pseuds/LadyDrace)




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